Comparison SanDisk Extreme Pro V30 SDXC UHS-I U3 128 GB vs SanDisk Extreme Pro V30 A1 microSD UHS-I U3 32 GB

General type of memory card.

— SD (Secure Digital). One of the most popular types of memory cards today. They measure 32x44 mm and have mechanical write protection in the form of a slider. Support for SD cards is almost a standard for modern laptops and digital cameras, and these media are also quite common in other devices (except for the most compact ones, where a reduced variety is used — microSD; it is described below). Note that today this type includes the following varieties:

• SDHC. Evolution of the outdated original SD standard. Maximum capacity increased to 32 GB, support for UHS speed bus is possible (see “UHS Class”), although such support is not mandatory. SDHC cards can be used in card readers of this format, as well as in devices for newer SDXC.
• SDXC. The newest SD card standard among the widely-used today. Allows for the creation of storage up to 2 TB; furthermore, it was in this standard that the UHS bus was first introduced (after which it was also applied to SDHC cards). In addition to card readers for this format, these media can also work with devices for SDHC — but only if the card is formatted in the FAT32 file system, while by default SDXC uses the exFAT system.

— microSD. A reduced version of the SD cards described above; the size of such a card is 15x11 mm. They are also very popular, but primarily in pocket technology — smartphones, tablets, portable players,...etc. Like the full-size version, they have varieties — microSDHC,

microSDXC. Application features are also similar: older cards can be used in newer card readers, but usually not vice versa.

— miniSD, miniSDHC. One of the reduced varieties of SD cards, preceding microSD(HC). Nowadays it is considered finally outdated and has almost fallen out of use.

— CompactFlash. One of the first formats of memory cards on the market. Includes two formats — CompactFlash Type I and CompactFlash Type II. They differ in reading/writing speed and sizes — Type II works faster and has a thickness of 5 mm (Type I — 3.3 mm with the same length and width of 42x36 mm). Due to this, a Type I card can be used with a reader for Type II, but not vice versa. Despite its venerable age, this format is still popular in photo equipment due to decent working speeds and capacities (up to 128 GB); the main drawback is large sizes compared to other formats.

— CFast 2.0. High-performance drives for fast operation with large data arrays. CFast 2.0 standard cards have the size of Compact Flash drives (42 x 36 mm), while boasting even more impressive reading and writing speeds (over 500 MB/s). This class of drives excels in recording video with high bitrates up to 8K resolution, as well as in reportage photography with high-speed continuous shooting in RAW. The memory capacity of CFast 2.0 drives can exceed 1 TB. Compatibility with memory cards of this standard is implemented in certain high-end cameras and camcorders.

— xD-Picture. A standard developed by Olympus and Fujifilm, mainly used in digital cameras of these companies. The main feature of these cards is the absence of a memory controller — thanks to this, they are reliable, compact (20x25 mm), and have low power consumption. On the other hand, the capacity of such cards is low (up to 2 GB), the reading speed is also quite low, and they are several times more expensive than similar media of the microSD format (including HC and XC). As a result, even the creators themselves are gradually shifting the emphasis towards other types of cards.

— MemoryStick. A proprietary standard developed by Sony specifically for its equipment back in 1998. It is closed and was almost never used in devices from other manufacturers. It was widely used until the early 2010s, when Sony began to gradually switch to the widespread SD standard. Nowadays, support for Memory Stick is extremely rare, mainly in outdated devices.
It should be noted that in this case, both original form-factor cards (50x21x2.8 mm) and Duo cards, which have reduced sizes (31x20x1.6 mm), can be implied. The third size, micro, is listed as a separate item (see below). However, all these form-factors are compatible through simple adapters.

— MemoryStick micro. The most miniature version of memory cards in the Memory Stick standard. For more details about this standard, see above; here, note that Memory Stick micro (also known as M2) has dimensions of 15x12.5x1.2 mm.

— XQD. Successors to CompactFlash cards, developed by the CompactFlash Association specifically for devices requiring high reading and writing speeds, particularly photo and video cameras — with practical writing speed reaching 125 MB/s, and there is evidence to suggest this is not the limit. At the same time, this card appeared relatively recently and is still gaining popularity. It has fairly large dimensions — 39x30x4 mm, larger than SD, although somewhat smaller than CompactFlash.

— CFexpress. Incredibly fast large-capacity drives designed for prolonged continuous recording in intensive mode. They are most suited for shooting video in 4K resolution and above at frame rates of 120 fps. Advanced series specimens provide writing and reading speeds exceeding 1 GB/s. Additionally, cards in this line are characterized by resistance to damage from drops and high bending strength. There are two types of CFexpress drives: Type A measuring 20x28x2.8 mm and Type B with dimensions of 38.5x29.8x3.8 mm.

— SxS. A memory card format developed jointly by Sony and SanDisk for professional-level video equipment. It uses the PCI Express interface, allowing such cards to be installed directly into an expansion card slot on a computer or laptop. It also features a high data transfer rate — up to 2.5 Gbps peak.

— PS Vita Card. A specialized memory card format designed, as the name implies, for portable gaming consoles PlayStation Vita. Created by Sony to replace UMD discs, it is not used by other manufacturers. It is proprietary, incompatible with universal standards like SD. The cards are available in capacities ranging from 4 to 64 GB.

— Nano Memory. A type of memory card introduced in 2018 by Huawei and mainly used in this brand's smartphones. Also colloquially known as nano SD, although this designation is technically incorrect. The size (area) of such media is 45% smaller than popular microSD cards, while Nano Memory cards are identical in size and contact placement to nanoSIM format SIM cards. This simplifies the use in smartphones with combined slots (suitable for both "sim" and memory card). As for characteristics, initially, Nano Memory was stated to have volumes up to 256 GB and reading speeds up to 90 MB/s; if this standard proves successful, we can expect these numbers to increase.

The nominal capacity of a memory card is the amount of data that can be written to it. For technical reasons, the real working volume of modern memory cards is usually somewhat less than the nominal one (for example, 14.9 GB with the claimed 16 GB). However, with the same type of card, differences in nominal capacity usually correspond to differences in actual capacity: for example, a 64 GB SDXC card will actually have twice the capacity of a 32 GB card of the same card.

Recall that different types of media have different limits on the maximum volume; see "Type" for details. And a specific volume is most often chosen by the manufacturer not arbitrarily, but from a list of standard options. The most widely used cards nowadays are 16 GB, 32 GB, 64 GB, 128 GB and 256 GB ; capacities of 8 GB or less are considered modest, with the most capacious models holding 512 GB or more.

Note that the price of the card directly depends on this parameter. Thus, many models are available in several variations, differing solely in capacity; and it is worth choosing by volume depending on the types of data that are planned to be stored on the card. Of the popular formats, text documents occupy the least space — usually tens, at most hundreds of kilo...bytes. The size of a photo from a modern camera or an MP3 file is already calculated in megabytes, music in lossless formats "weighs" already tens of megabytes, and the volume of a video depends on its duration, resolution and the codecs used.

Speed class when working with applications to which the memory card corresponds.

When working with applications that use a memory card (for example, mobile games), information is written and read not in a continuous stream, as when recording video or copying data, but in separate small fragments, and from random areas in the drive’s memory (the so-called random write/read). So a high-class video recording (see above) does not always mean good flow Rate when working with demanding games and other resource-intensive programs. Therefore, the characteristics of memory cards began to separately indicate the speed class for applications.

The key indicator for assigning a particular class is the minimum number of IOPS (input/output operations per second) that the media can provide in random write and read mode. Nowadays, the following classes are relevant:

— A1 — at least 1500 IOPS for reading and 500 IOPS for writing;

— A2 — at least 4000 IOPS and 2000 IOPS, respectively.

The continuous recording speed (for example, when recording video) in both cases must be at least 10 MB/s (often it is higher - see “Speed class”, “Video recording class”).

In the future, we can expect the emergence of new, more productive classes for applications. We also note that this parameter significantly affects the price of the card.

The coefficient describing the maximum speed of the card in read mode. In this case, 150 KB/s is taken as a unit; thus, for example, the speed value of 533x corresponds to 150*533=79,950 KB/s, i.e. about 80 MB/s.

In general, this parameter is quite specific; in practice, it is easier to focus on the directly declared reading speed (see below). However, sometimes it is not specified - in such cases, the speed value will be most useful.

The maximum speed of reading data from a memory card.

Any modern memory card provides sufficient reading speed for simple everyday tasks — like copying photos from a camera to a laptop. Therefore, it makes sense to pay attention to this parameter mainly in cases where the card is purchased for professional use, or if high speed is critical for you — for example, if you often have to copy photos from the camera in a hurry. In doing so, two points should be taken into account. Firstly, the corresponding speed must be supported by the card reader where the card is used. Secondly, this paragraph indicates the theoretical maximum — in perfect conditions; the actual reading speed may be lower (if we are talking about cards with UHS, this speed can be estimated by the UHS class, see above about it). Nevertheless, it is quite possible to compare different models of cards by this indicator: differences in theoretical speed usually quite correspond to the difference in actual speed.

The ability to switch the card to read-only mode, which allows you to protect important data from accidental overwriting or erasure. Usually implemented in the form of a mechanical slider switch, the position of which determines the card's operating mode. However, it is worth considering that this slider is only an indicator that signals the card reader about the selected mode, and its position does not affect the card itself; in some card readers, the write protection function may simply be absent - such devices will not "see" the position of the slider.

An additional adapter is included with the memory card.

The adapter is a device with which the card can be installed in a non-native format card reader. Nowadays, microSD cards are mainly equipped with such a device — adapters are designed to install such media in a slot for a full-size SD card. This is convenient primarily for exchanging data between portable gadgets like a smartphone / tablet and larger equipment like PCs and laptops — for example, to copy pictures from a smartphone camera to a computer or music from a computer to a smartphone.